There is increased interest in the ability to reduce small diameter trees, branches, logging residue and the like to pieces of usable size as for example for use as pulp in paper manufacture, chunk size for firing boilers and for flake boards and also in the production of firewood or fuel wood. Prior art devices have concentrated on the utilization of disc-type cutting devices which reduce a log to chips or prepare a log for further use as in lumber.
U.S. Pat. No. 3,190,326 to Standal discloses an invention for squaring logs in preparation for sawmill processing. The logs are fed in a radial way while a circular multi-bladed wheel spins to cut the log into chips.
U.S. Pat. No. 3,360,024 to Traben discloses a multi-bladed chipping device which is radially presented to a log. The device is utilized for squaring a log for sawmill processing at a later time.
U.S. Pat. No. 3,461,931 to Wexell describes a wood chipping device which utilizes holes in which chipping blades have been mounted so that a log which has been presented in an axial way to the cutting machine may be reduced to chips. The cutting chamber itself is conical thereby progressively reducing the diameter of the log presented as the log is reduced to chips.
U.S. Pat. No. 4,135,563 to Maucher discloses an apparatus for chipping logs in which the logs are presented in an essentially radial manner to a drum-type chipping device in which the blades have been mounted on a spinning drum.
U.S. Pat. No. 4,311,175 to Drummond discloses a log-chipping apparatus in which the logs are presented in an axial manner to a plate which is rotating and which bears the chipping tools.
Among the problems inherent in prior art logging chipping devices is that they will tend to jam when presented with too large a log, thus requiring dismantling or at least time consuming work to extract the oversized jammed log from the machine, during which time no processing can proceed. Additionally, a number of the prior art devices have the problem of having the power source mounted adjacent to or below the point of chipping, the chips produced may then fall into the mechanical apparatus causing fouling of the drive apparatus.
Therefore, here is a need for an improved wood chipping apparatus which will avoid the problems of jamming when presented with an oversized log and which will maintain the drive equipment at such a location that it will not be fouled by the falling chips of wood. Additionally, it is desirable to have an apparatus which will produce wood products of varying sizes depending upon the ultimate use to be made of products. Prior art machines are not versatile in that they produce a single size chip under any set of circumstances and would need new blades in order to produce a different size chip. Therefore, there is a need for a wood severing apparatus in which the size of the pieces to which a log is reduced may be varied at will without major reconstruction of the machine.